NR ABAX
AU Baskakov,I.V.; Legname,G.; Baldwin,M.A.; Prusiner,S.B.; Cohen,F.E.
TI Pathway complexity of prion protein assembly into amyloid
QU The Journal of Biological Chemistry 2002 Jun 14; 277(24): 21140-8
IA http://www.jbc.org/cgi/content/full/277/24/21140
PT journal article
AB In vivo under pathological conditions, the normal cellular form of the prion protein, PrPc (residues 23-231), misfolds to the pathogenic isoform PrPsc, a beta-rich aggregated pathogenic multimer. Proteinase K digestion of PrPsc leads to a proteolytically resistant core, PrP 27-30 (residues 90-231), that can form amyloid fibrils. To study the kinetic pathways of amyloid formation in vitro, we used unglycosylated recombinant PrP corresponding to the proteinase K-resistant core of PrPsc and found that it can adopt two non-native abnormal isoforms, a beta-oligomer and an amyloid fibril. Several lines of kinetic data suggest that the beta-oligomer is not on the pathway to amyloid formation. The preferences for forming either a beta-oligomer or amyloid can be dictated by experimental conditions, with acidic pH similar to that seen in endocytic vesicles favoring the beta-oligomer and neutral pH favoring amyloid. Although both abnormal isoforms have high beta-sheet content and bind 1-anilinonaphthalene-8-sulfonate, they are dissimilar structurally. Multiple pathways of misfolding and the formation of distinct beta-sheet-rich abnormal isoforms may explain the difficulties in refolding PrPsc in vitro, the need for a PrPsc template, and the significant variation in disease presentation and neuropathology.
MH Amyloid/*chemistry; Anilino Naphthalenesulfonates/pharmacology; Animals; Chromatography, High Pressure Liquid; Circular Dichroism; Cricetinae; Dimerization; Dose-Response Relationship, Drug; Endopeptidase K/pharmacology; Epitopes; Fluorescent Dyes/pharmacology; Hydrogen-Ion Concentration; Kinetics; Light; Mesocricetus; Mice; Microscopy, Electron; Prions/*chemistry/*metabolism; Protein Binding; Protein Conformation; Protein Folding; Protein Isoforms; Protein Structure, Secondary; Protein Structure, Tertiary; Recombinant Proteins/chemistry; Research Support, U.S. Gov't, P.H.S.; Scattering, Radiation; Spectrum Analysis, Mass; Time Factors
AD Institute for Neurodegenerative Diseases, University of California, San Francisco, California 94143, USA
SP englisch
PO USA